Eh I'm for a silent protagonist in MMO type games. In fact, I don't even really like when some of the main NPCs refer to your character as special or anything since we know there are so many other players doing the same thing. Like in that beta story mission, someone refers to you as "That guardian you always talk about". Or in other MMOs where your character is like the hero meant to save the world, when you know that every other player is also that hero. I'd prefer if your character was just a side character of the larger plot.
But I suppose it is probably hard to write a story that actually takes into account all the other players in the game, make the player feel good about what they're doing, and also is interesting.